1. Field of the Invention
The present invention relates to a switching protocol in a packet switching network and more particularly to a system and method of providing a high speed protocol for switch devices in a packet switching network.
2. Description of the Related Art
A packet switching network/fabric may include one or more network devices, such as an Ethernet switching chip, each of which includes several modules that are used to process information that is transmitted through the device. Specifically, each network device includes an ingress module, a Memory Management Unit (MMU) and an egress module. The ingress module includes switching functionality for determining to which destination port a packet should be directed. The MMU is used for storing packet information and performing resource checks. The egress module is used for performing packet modification and for transmitting the packet to at least one appropriate destination port. One of the ports on the device may be a CPU port that enables the device to send and receive information to and from external switching/routing control entities or CPUs.
One or more network devices in a switching fabric may include one or more internal fabric high speed ports, for example a HiGig™ port, in addition to one or more external Ethernet ports, and a CPU port. The high speed ports are used to interconnect various network devices in a system and thus form an internal switching fabric for transporting packets between external source ports and one or more external destination ports. As such, the high speed ports are not externally visible outside of a system that includes multiple interconnected network devices. The current high speed transmission protocols for these high speed ports, however, have become an architectural bottle neck because they do not scale well with the requirements from higher end system designs. For example, the current high speed transmission protocols support eight classes which are not enough to differentiate system control and network application traffic within the switching fabric. Current high speed transmission protocols also support up to 128 modules which is insufficient for higher end system design and expansion. In current high speed transmission protocols, the support of 4K identifiers in each of the layer 2 multicast and IP multicast space is not enough, in some cases, and the hard separation of layer 2 multicast, IP multicast and broadcast spaces makes it inflexible to re-allocate limited table resources to meet requirements from different customers' system designs. Furthermore, the design of the header structure of the current high speed transmission protocols prevents sustainable development. In addition, important information in missing. For example, missing from the current high speed transmission protocols are load balancing information which enables every port of switching fabric to have its own packet parsing logic and a fine granular link level flow control mechanism for optimal operation required by higher end fabric designs.